In recent years, multicast transmission has been supported in various types of electronic devices. Multicast transmission is a communication scheme in which a transmission side designates a plurality of destinations and transmits one packet. For example, when multimedia content is transmitted, multicast is widely used due to its efficiency.
When a reception terminal succeeds in receiving a packet in multicast transmission, the reception terminal responds to the transmission side with an acknowledge response (ACK response). Thus, the transmission side can know a reception result of each reception terminal, thereby improving a probability of success of multicast transmission by performing a retransmission process based on the reception result. However, since the number of ACK responses increases with an increase in the number of reception terminals, transmission opportunities from the transmission side decrease, thereby deteriorating the throughput of multicast transmission. This tendency occurs more considerably when wireless resources used for the transmission and reception overlap. For this reason, technologies for improving the throughput by reducing the number of ACK responses have been developed.
For example, PTL 1 discloses a technology for grouping wireless nodes based on reception strengths when a base station receives transmission packets from the wireless nodes and deciding a representative node to respond with an ACK response to multicast transmission for each group.
PTL 2 discloses a technology for deciding a reception terminal to respond with an ACK response to multicast transmission from a transmission terminal based on distances between the transmission terminal and reception terminals.